Abstract
Carbazole is an irreplaceable basic organic chemical raw material and intermediate in industry.The sep-aration of carbazole from anthracene oil by environmental benign solvents is important but still a chal-lenge in chemical engineering.Deep eutectic solvents(DESs)as a sustainable green separation solvent have been proposed for the separation of carbazole from model anthracene oil.In this research,three quaternary ammonium-based DESs were prepared using ethylene glycol(EG)as hydrogen bond donor and tetrabutylammonium chloride(TBAC),tetrabutylammonium bromide or choline chloride as hydro-gen bond acceptors.To explore their extraction performance of carbazole,the conductor-like screen-ing model for real solvents(COSMO-RS)model was used to predict the activity coefficient at infinite dilution(γ∞)of carbazole in DESs,and the result indicated TBAC:EG(1:2)had the stronger extraction ability for carbazole due to the higher capacity at infinite dilution(C∞)value.Then,the separation per-formance of these three DESs was evaluated by experiments,and the experimental results were in good agreement with the COSMO-RS prediction results.The TBAC∶EG(1∶2)was determined as the most promising solvent.Additionally,the extraction conditions of TBAC∶EG(1∶2)were optimized,and the extraction efficiency,distribution coefficient and selectivity of carbazole could reach up to 85.74％,30.18 and 66.10％,respectively.Moreover,the TBAC∶EG(1∶2)could be recycled by using environmentally friendly water as antisolvent.In addition,the separation performance of TBAC∶EG(1∶2)was also evalu-ated by real crude anthracene,the carbazole was obtained with purity and yield of 85.32％,60.27％,respectively.Lastly,the extraction mechanism was elucidated by σ-profiles and interaction energy anal-ysis.Theoretical calculation results showed that the main driving force for the extraction process was the hydrogen bonding((N-H… Cl)and van der Waals interactions(C-H…O and C-H …π),which corresponding to the blue and green isosurfaces in IGMH analysis.This work presented a novel method for separating carbazole from crude anthracene oil,and will provide an important reference for the separation of other high value-added products from coal tar.
基金项目
Shanxi Province Natural Science Foundation of China(20210302123167)
NSFC-Shanxi joint fund for coalbased low carbon(U1610223)
Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(2021SX-TD006)
NETL
NSTL
万方数据